Random Number Generator (RNG)

XPR Network provides an easy to use way to get random numbers on the blockchain.

Request Random Number

RNG requests using sendRequestRandom require 3 parameters from you:

• contract - Name - Contract to call receiverand action on once random number is generated.
• requestId - u64 - Any ID to tie the RNG request to your own data.
• signingValue - u64 - A value which will be used by the RNG provider to create a random checksum.

import { Name, check, requireAuth, Contract, Checksum256, TableStore } from 'proton-tsc'
import { sendRequestRandom, rngChecksumToU64 } from 'proton-tsc/rng';

@contract
class Rng extends Contract {
    @action("myaction")
    myaction(
        requestId: u64,
        signingValue: u64
    ): void {
        // ... Authenticate if needed ...
        
        // ... Save account, requestId and signing value to a table ...

        // Send RNG request
        sendRequestRandom(this.receiver, requestId, signingValue)
    }
}

Receive Random Number

The random number generator will call the receiverand action on your contract with:

• requestId - u64 - Any ID to tie the RNG request to your own data
• randomChecksum - Checksum256 - A random checksum based off of the signingValue provided

import { Name, check, requireAuth, Contract, Checksum256, TableStore } from 'proton-tsc'
import { sendRequestRandom, rngChecksumToU64, RNG_CONTRACT } from 'proton-tsc/rng';

@contract
class Rng extends Contract {
    // ... code for requesting RNG value ...

    @action("receiverand")
    receiverand(
      requestId: u64,
      randomChecksum: Checksum256,
    ): void {
        // Authenticate
        requireAuth(RNG_CONTRACT);

        // ... Get data from your own tables using requestId ...

        // Set random value (100 is used as max value here)
        const randomValue = rngChecksumToU64(randomChecksum, 100);
    }
}